High Efficiency WCDMA Power Amplifier for MUOS Handheld Radio

The MUOS system has a critical need for an efficient power amplifier capable of delivering 8W of RF power with a 2 to 3 dB higher peak-to-average ratio than typical WCDMA. Quantum Dimension’s approach is to provide technology innovation by incorporating cutting-edge RF circuit and system design with advanced digital signal processing. Our approach involves: new transistor technology with increased efficiency, use of Doherty circuit topology, pre-distortion and peak envelope following that dramatically increases efficiency. It minimizes risk and complexity in order to meet challenging efficiency and output power requirements. While other researchers have focused on specific applications of envelope following, we feel that combining our innovative RF design with advanced signal processing more effectively increases power efficiency to meet >50% improvement as required for MUOS. We will study present PA transistor devices for handsets and select the most appropriate technology. Additionally, we develop and model large RF bandwidth methods and simulate Doherty PA structures with peak envelope following and pre-distortion for Class AB and Doherty PA’s. This allows us to quantify fundamental performance and employ system models. Finally, we develop signal and system models with current drain and distortion estimates for Doherty PA with pre-distortion and peak envelope following.